Start up backend and rendering loop

README.md

@@ -3,4 +3,16 @@
 This is a demonstration Wayland compositor that accompanies a series of blog
 posts written for [drewdevault.com](https://drewdevault.com).
 
-This is the initial commit.
+- **[Part 1: Hello wlroots](https://drewdevault.com/2018/02/17/Writing-a-Wayland-compositor-1.html)** (you are here)
+
+## Compiling
+
+```shell
+mkdir build
+cd build
+meson ..
+ninja
+```
+
+This will produce a binary named `mcwayface`, this is your compositor. Run it
+without any arguments.

meson.build

@@ -24,9 +24,18 @@ endif
 # Avoid wl_buffer deprecation warnings
 add_project_arguments('-DWL_HIDE_DEPRECATED', language: 'c')
 
+pixman         = dependency('pixman-1')
+wlroots        = dependency('wlroots')
+wayland_server = dependency('wayland-server')
+
 executable(
 	'mcwayface',
 	[
 		'src/main.c'
 	],
+	dependencies: [
+		pixman,
+		wlroots,
+		wayland_server,
+	]
 )

src/main.c

@@ -1,6 +1,125 @@
+#define _POSIX_C_SOURCE 200809L
+#include <assert.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <wayland-server.h>
+#include <wlr/backend.h>
+#include <wlr/render.h>
+
+struct mcw_server {
+	struct wl_display *wl_display;
+	struct wl_event_loop *wl_event_loop;
+
+	struct wlr_backend *backend;
+
+	struct wl_listener new_output;
+
+	struct wl_list outputs; // mcw_output::link
+};
+
+struct mcw_output {
+	struct wlr_output *wlr_output;
+	struct mcw_server *server;
+	struct timespec last_frame;
+	float color[4];
+	int dec;
+
+	struct wl_listener destroy;
+	struct wl_listener frame;
+
+	struct wl_list link;
+};
+
+static void output_frame_notify(struct wl_listener *listener, void *data) {
+	struct mcw_output *output = wl_container_of(listener, output, frame);
+	struct wlr_output *wlr_output = data;
+	struct wlr_renderer *renderer = wlr_backend_get_renderer(
+			wlr_output->backend);
+
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+
+	// Calculate a color, just for pretty demo purposes
+	long ms = (now.tv_sec - output->last_frame.tv_sec) * 1000 +
+		(now.tv_nsec - output->last_frame.tv_nsec) / 1000000;
+	int inc = (output->dec + 1) % 3;
+	output->color[inc] += ms / 2000.0f;
+	output->color[output->dec] -= ms / 2000.0f;
+	if (output->color[output->dec] < 0.0f) {
+		output->color[inc] = 1.0f;
+		output->color[output->dec] = 0.0f;
+		output->dec = inc;
+	}
+	// End pretty color calculation
+
+	wlr_output_make_current(wlr_output, NULL);
+	wlr_renderer_begin(renderer, wlr_output);
+
+	wlr_renderer_clear(renderer, &output->color);
+
+	wlr_output_swap_buffers(wlr_output, NULL, NULL);
+	wlr_renderer_end(renderer);
+
+	output->last_frame = now;
+}
+
+static void output_destroy_notify(struct wl_listener *listener, void *data) {
+	struct mcw_output *output = wl_container_of(listener, output, destroy);
+	wl_list_remove(&output->link);
+	wl_list_remove(&output->destroy.link);
+	wl_list_remove(&output->frame.link);
+	free(output);
+}
+
+static void new_output_notify(struct wl_listener *listener, void *data) {
+	struct mcw_server *server = wl_container_of(
+			listener, server, new_output);
+	struct wlr_output *wlr_output = data;
+
+	if (wl_list_length(&wlr_output->modes) > 0) {
+		struct wlr_output_mode *mode =
+			wl_container_of((&wlr_output->modes)->prev, mode, link);
+		wlr_output_set_mode(wlr_output, mode);
+	}
+
+	struct mcw_output *output = calloc(1, sizeof(struct mcw_output));
+	clock_gettime(CLOCK_MONOTONIC, &output->last_frame);
+	output->server = server;
+	output->wlr_output = wlr_output;
+	output->color[0] = 1.0;
+	output->color[3] = 1.0;
+	wl_list_insert(&server->outputs, &output->link);
+
+	output->destroy.notify = output_destroy_notify;
+	wl_signal_add(&wlr_output->events.destroy, &output->destroy);
+	output->frame.notify = output_frame_notify;
+	wl_signal_add(&wlr_output->events.frame, &output->frame);
+}
 
 int main(int argc, char **argv) {
-	printf("hello wlroots\n");
+	struct mcw_server server;
+
+	server.wl_display = wl_display_create();
+	assert(server.wl_display);
+	server.wl_event_loop = wl_display_get_event_loop(server.wl_display);
+	assert(server.wl_event_loop);
+
+	server.backend = wlr_backend_autocreate(server.wl_display);
+	assert(server.backend);
+
+	wl_list_init(&server.outputs);
+
+	server.new_output.notify = new_output_notify;
+	wl_signal_add(&server.backend->events.new_output, &server.new_output);
+
+	if (!wlr_backend_start(server.backend)) {
+		fprintf(stderr, "Failed to start backend\n");
+		wl_display_destroy(server.wl_display);
+		return 1;
+	}
+
+	wl_display_run(server.wl_display);
+	wl_display_destroy(server.wl_display);
 	return 0;
 }